Recent Advances in Sequence‐Controlled Ring‐Opening Copolymerizations of Monomer Mixtures

Abstract

Transforming renewable resources into functional and degradable polymers is driven by the ever‐increasing demand to replace unsustainable polyolefins. However, the utility of many degradable homopolymers remains limited due to their inferior properties compared to commodity polyolefins. Therefore, the synthesis of sequence‐defined copolymers from one‐pot monomer mixtures is not only conceptually appealing in chemistry, but also economically attractive by maximizing materials usage and improving polymers’ performances. Among many polymerization strategies, ring‐opening (co)polymerization of cyclic monomers enables efficient access to degradable polymers with high control on molecular weights and molecular weight distributions. Herein, we highlight recent advances in achieving one‐pot, sequence‐controlled polymerizations of cyclic monomer mixtures using a single catalytic system that combines multiple catalytic cycles. The scopes of cyclic monomers, catalysts, and polymerization mechanisms are presented for this type of sequence‐controlled ring‐opening copolymerization.

Structural Metamorphoses of d-Xylose Oxetane- and Carbonyl Sulfide-Based Polymers In Situ during Ring-Opening Copolymerizations

“…The quest for degradable, sustainable polymers from renewable resources is becoming an increased priority, along with and in efforts to address coincident events of plastic pollution, climate change, and the energy transition away from petroleum-based feedstocks. There has been an emphasis on developing chemical transformations involving molecular or macromolecular materials of natural origin to afford functional polymers, thereby advancing efforts toward achieving sustainability for the growing plastic demand. − Relevant to this aim, copolymerizations of small molecule natural products with carbon dioxide or other complementary feedstocks, some of which originate as waste from fossil fuel or human-made supplies, are of particular interest for the production of a broad range of types of sustainable polymeric materials. ,− For instance, the general class of ring-opening copolymerizations (ROCOPs) ,− ,− of cyclic ethers with comonomers, such as carbon dioxide (CO 2 ), ,− carbonyl sulfide (COS), , carbon disulfide (CS 2 ), , aryl isocyanates, , and cyclic anhydrides, ,,,,− has provided access to diverse backbone compositions, including polycarbonates, poly­(monothiocarbonate)­s, poly­(thiocarbonate)­s, polyurethanes or polyallophanates, and polyesters, respectively. However, a common limitation to this copolymerization strategy is the use of cyclic ethers from non-renewable sources, which adversely affects overall sustainability.…”

Dinuclear chromium complexes with [OSSO]-type ligands in the copolymerization of epoxides with CO2and phthalic anhydride

“…More recently, attention has shifted to the terpolymerization of epoxides with CO 2 and cyclic anhydrides for the possibility of obtaining block copolymers with polycarbonate and polyester segments having different microstructural features and therefore offering a wider range of chemical and physical properties. 19–21…”

Cationic Ring-Opening Copolymerization of Cyclic Acetals and 1,3-Dioxolan-4-ones via the Activated Monomer Mechanism and Transacetalization Reaction

“…Cationic ring-opening copolymerizations between different types of cyclic monomers, such as cyclic ethers, cyclic esters, and cyclic acetals, exert great potential, particularly in controlling monomer sequences, tuning the physical properties of polymers, providing copolymers with degradability, and overcoming inertness, such as nonhomopolymerizability. − The features attained by copolymerization rather than homopolymerization are ascribed to various possible reactions, such as propagation, backbiting, and transacetalization reactions, that occur during cationic ring-opening polymerization. In addition, two main types of propagation mechanisms may occur in cationic ring-opening polymerization.…”